import React, { Component } from "react";

export default class Demo extends Component {
  state = { count: 0 };

  add = () => {
    const { count } = this.state;
    //对象式写法
    // this.setState({count:count+1},()=>{
    //     console.log(this.state.count)
    // })

    //函数式写法
    this.setState(state =>({ count: state.count + 1 }));

  };

  render() {
    return (
      <div>
        <h1>当前求和为：{this.state.count}</h1>
        <button onClick={this.add}>加一</button>
      </div>
    );
  }
}
